3Com 5500G, 4210, 4200G manual Configuring Digest Snooping and Rapid Transition

88CHAPTER 14: MSTP CONFIGURATION GUIDE

interface Ethernet1/0/8

stp disable

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3Configuration on Switch C

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stp instance 0 priority 8192 stp enable

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interface Ethernet1/0/1 stp root-protection

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interface Ethernet1/0/2 stp root-protection

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interface Ethernet1/0/3 stp root-protection

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interface Ethernet1/0/8 stp disable

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4Configuration on Switch D

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stp enable

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interface Ethernet1/0/3 stp disable interface Ethernet3/0/5 stp edged-port enable stp bpdu-protection

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Configuring Digest

Snooping and Rapid

Transition

Digest Snooping On a network comprised of devices of multiple vendors, 3Com switches cannot interoperate with switches that run proprietary spanning tree protocols in the same MSTP region, even if they are configured with the same MST region-related settings.

To address the problem, you can enable digest snooping on the ports connected to switches running proprietary spanning tree protocols.

Rapid Transition The proprietary spanning tree protocols of some vendors provide port state transition mechanisms similar to RSTP. For a switch running such a proprietary protocol, its rapid port state transition mechanism may fail on the designation port when the switch is downlinked to an MSTP-enabled 3Com switch.

To address the problem, you can enable the rapid transition feature on the downstream 3Com switch.